If you go behind someone's back to undermine something they really want, even if it's for what you think is a good reason, you'll lose their trust. It's called a betrayal. And that means they're going to be less likely to cooperate with you the next time you really need or want them to. This applies to anyone. Even your teammates.
And if the members of a team can't even trust each other, that team's going to crack over time. Especially when it comes to a Game or any other instance where how well we can work together could mean the difference between life and death.